Apparatus of plural charged-particle beams

Abstract

A multi-beam apparatus for observing a sample with high resolution and high throughput is proposed. In the apparatus, a source-conversion unit changes a single electron source into a virtual multi-source array, a primary projection imaging system projects the array to form plural probe spots on the sample, and a condenser lens adjusts the currents of the plural probe spots. In the source-conversion unit, the image-forming means is on the upstream of the beamlet-limit means, and thereby generating less scattered electrons. The image-forming means not only forms the virtual multi-source array, but also compensates the off-axis aberrations of the plurality of probe spots.

1 - 24 . (canceled) 
     
     
         25 . A charged-particle beam apparatus, comprising:
 a source conversion unit configured to convert electrons from a single electron source into a plurality of beamlets, the source conversion unit comprising a plurality of paired elements,   wherein each paired element comprises a first element and a second element above the first element, and   the first elements of the plurality of paired elements form a first layer of multi-pole elements and the second elements of the plurality of paired elements form a second layer of multi-pole elements; and   a beam-limiting element having a plurality of beam-limit openings for limiting the plurality of beamlets.   
     
     
         26 . The charged-particle beam apparatus of  claim 25 , wherein the beam-limiting element is positioned below the source conversion unit. 
     
     
         27 . The charged-particle beam apparatus of  claim 25 , wherein the beam-limiting element is a beam-limiting plate. 
     
     
         28 . The charged-particle beam apparatus of  claim 25 , wherein the beam-limit openings comprise multiple sizes. 
     
     
         29 . The charged-particle beam apparatus of  claim 25 , wherein the multi-pole elements of the first layer are aligned with the multi-pole elements of the second layer in a direction parallel to a primary optical axis of the apparatus. 
     
     
         30 . The charged-particle beam apparatus of  claim 25 , further comprising a first projection system configured to form a plurality of probe spots on a sample from the plurality of beamlets. 
     
     
         31 . The charged-particle beam apparatus of  claim 30 , further comprising a second projection system configured to focus a plurality of secondary beams generated by the plurality of probe spots on the sample. 
     
     
         32 . The charged-particle beam apparatus of  claim 31 , further comprising a detection device configured to receive the plurality of secondary beams. 
     
     
         33 . The charged-particle beam apparatus of  claim 31 , further comprising a beam separator configured to separate the plurality of beamlets and the plurality of secondary beams. 
     
     
         34 . The charged-particle beam apparatus of  claim 30 , further comprising: a condenser lens configured to focus a primary beam to vary electric currents of the plurality of probe spots on the sample. 
     
     
         35 . A charged-particle beam apparatus, comprising:
 a source conversion unit configured to convert electrons from a single electron source into a plurality of beamlets, the source conversion unit comprising a plurality of paired elements,   wherein each paired element comprises a first element and a second element, and   the first elements of the plurality of paired elements form a first layer of multi-pole elements and the second elements of the plurality of paired elements form a second layer of multi-pole elements; and   a beam-limiting element configured to receive the plurality of beamlets to limit the plurality of beamlets.   
     
     
         36 . The charged-particle beam apparatus of  claim 35 , wherein the beam-limiting element is positioned below the source conversion unit. 
     
     
         37 . The charged-particle beam apparatus of  claim 35 , wherein the beam-limiting element is a beam-limiting plate. 
     
     
         38 . The charged-particle beam apparatus of  claim 35 , wherein the beam-limiting element has a plurality of beam-limit openings for limiting the plurality of beamlets. 
     
     
         39 . The charged-particle beam apparatus of  claim 35 , wherein the multi-pole elements of the first layer are aligned with the multi-pole elements of the second layer in a direction parallel to a primary optical axis of the apparatus. 
     
     
         40 . The charged-particle beam apparatus of  claim 35 , further comprising a first projection system configured to form a plurality of probe spots on a sample from the plurality of beamlets. 
     
     
         41 . The charged-particle beam apparatus of  claim 40 , further comprising a second projection system configured to focus a plurality of secondary beams generated by the plurality of probe spots on the sample. 
     
     
         42 . The charged-particle beam apparatus of  claim 41 , further comprising a detection device configured to receive the plurality of secondary beams. 
     
     
         43 . The charged-particle beam apparatus of  claim 41 , further comprising a beam separator configured to separate the plurality of beamlets and the plurality of secondary beams. 
     
     
         44 . The charged-particle beam apparatus of  claim 40 , further comprising: a condenser lens configured to focus a primary beam to vary electric currents of the plurality of probe spots on the sample.